In a wireless communication system, a mobile station (MS) is assigned a frequency sub-channel and a time slot in a physical layer for its communications with a base station, nodeB, or access point (AP). Since there are limited resources in existing systems (note that there are two dimensions to the resources—time and frequency, hence the total available resource=bandwidth*time), frequency reuse plans can be utilized to share the same resources between different cells. Reusing the same resources in all sectors all the time can result in interference between neighboring MSs that are using the same frequency at the same time. This plan, referred to as a one-cell reuse, is a spectrally efficient reuse scheme for users close in to a cell site (e.g. 114 in FIG. 1B and 1C) but suffers from heavy interference issues for cell-edge users (e.g. 112 in FIG. 1B and 1C).
Fractional frequency reuse plans can be used for separate sectors within a single cell. One form of fractional frequency reuse plan that can be used for a single cell is to limit each sector to use only a fraction of the available resources for the cell site (such that the sum of the mutually disjoint fractions equals the total available resources). Examples of this plan are (in a N-sector per site system—e.g., N could be 3 or 4): (a) Allocate 1/N of the total bandwidth to each sector all the time, (b) Allocate the full bandwidth to each sector for 1/N of the time. This plan, referred to as multi-cell reuse plan, effectively reduces interference, but results in the loss of (N−1)/N resources within each sector, even for users that are closer in to the cell site and who don't suffer as much interference. Although this multi-cell reuse plan offers lower interference for cell edge users (e.g. 112 in FIG. lB and 1C), it is not spectrally efficient for users close in to the cell site (e.g. 114 in FIG. lB and 1C).
There is currently no fractional frequency reuse (FFR) technique that performs better than the one-cell reuse and multi-cell reuse fractional frequency reuse plans across different traffic models.
Accordingly, what is needed is a technique to mitigate the problems associated with the one-cell reuse and multi-cell reuse FFR reuse plans.
Skilled artisans will appreciate that common but well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted or described in order to facilitate a less obstructed view of these various embodiments of the present invention.